The present invention relates to a can opener with two pivotally connected levers in laid down position, and more particularly a can opener, which ensures that the cut around the periphery of the top forms a loop, and which can be operated smoothly.
To avoid shavings formed in can openers opening a can from contaminating the contents of the can, and to prevent the cut can top from falling into the can contents, can openers have been developed that are designed to cut the outside seam wall at the top of the can.
Referring to FIGS. 9 and 10, a can opener designed with the above mentioned function, disclosed in U.S. Pat. No. 5,121 546, includes a housing 40, a cutting wheel 80, and a traction wheel 140. The cutting wheel 80 has a spindle defining a cutting wheel axis, while the traction wheel 140 has a spindle 180 defining a traction wheel axis. A fixed thrust surface fixed to the housing and a movable thrust surface associated with the traction wheel spindle are provided. A finger-actuated lever 380 is pivoted to the housing, and can be inserted into between the thrust surfaces from a throat section equipped with ball bearings 320 such that the movable thrust surface is moved away from the fixed thrust surface to move the traction wheel closer to the cutting wheel. Both the traction wheel 140 and the cutting wheel 80 define a gap adapted to accept a can seam wall to be opened. When the lever 380 is moved close to a handle 60 of the housing 40, the spindle 180 is moved along the axis so that the traction wheel 140 is moved toward the cutting wheel 140 to close the gap thereby engaging and locking the can between the cutting wheel and the traction wheel; the traction wheel acts to move the can past the cutting wheel for allowing the cutting wheel to cut the outer wall of the can when a knob 360 connected to the spindle 180 is turned.
In this regard, the ball bearings 320 provide a bearing surface to allow thrust surface 280 affixed to the spindle 180 to rotate freely with respect to fixed traction surface 260. However, the traction wheel is subject to diversion in the course of turning because the ball bearings 320 are not spaced apart, hindering the smooth operation of the can opener. Furthermore, abutment means are provided for guiding the movement of the can opener about the can during a cutting operation, which include a shoulder adapted to abut the top and outside seam wall edges in front of the cutting and traction wheels. However, when the section of the can that has been passed through the opener, and cut by the cutting wheel is moved under the shoulder, the opener is likely to be displaced from the original appropriate position because this can section is raised due to the cutting. Consequently, the cut around the periphery of the can top fails to form a loop, hindering easy removal of the can top.
Referring to FIG. 11, another can opener, disclosed in U.S. Pat. No. 5,367,776, includes a handle, a first thrust surface 260 associated with the housing and a spaced, adjacent, second thrust surface 280 associated with the movable wheel. The first and second thrust surfaces comprises cooperable cam surfaces rotatable relative to each other to reciprocate the first and second thrust surfaces relative to each other between a first position where a gap between a cutting wheel and a traction wheel to receive a can seam wall is relatively wide, and a second position where the can seam wall is engaged and locked between the cutting wheel and the traction wheel. The handle permits one of the wheels to be rotated by hand. This structure overcomes the drawback of the last can opener that the traction wheel is subject to diversion in the course of turning because the ball bearings are not spaced apart. However, the traction wheel and the cutting wheel fail to squeeze the can seam wall firmly in between like the last opener. In addition, a space must be provided between the lever and the handle for allowing easy downward movement of the lever. Consequently, the lever is prone to unwantedly move in sideways direction that is different from the intended one of the pivotal movement, therefore it would be relatively difficult to move the lever down, and the lever would cause deformation of the spindle if forced to move down. And, movement guiding abutment means provided to it has the same drawback as the last opener.
Referring to FIG. 12, the inventor of the present invention has invented a can opener disclosed in U.S. Pat. No. 5,946,811 plus Taiwan patent no. 327896. However, this can opener also has the same disadvantages as the above mentioned ones.
Therefore, it is a main object of the present invention to provide a can opener, which can be operated smoothly and with precision.
It is another object of the present invention to provide a can opener, which ensures that the cut around the periphery of the can forms a loop for allowing easy removal of the can top.
The present can opener includes a first lever, and a second lever pivotally connected to the first lever. The levers are held in laid down position for allowing a traction wheel and a cutting wheel to squeeze a top seam wall of a can. The first lever is equipped with a first wheel having domed protrusions spaced around the center. The second lever is equipped with a second wheel having first recesses spaced around the center. Shallower second recesses and shallowest curved trenches are formed between the first recesses; the curved trenches are similar to annular trenches provided on trust block seating of thrust ball bearings. Spindle of the traction wheel is passed through the centers of the wheels of the levers to be affixed to an actuating member. The traction wheel is biased to be away from the cutting wheel with springs for a can seam wall to be inserted into between the same when the domed protrusions are held in the first recesses. The second wheel pushes both the first wheel and the actuating member further away from the second lever when the domed protrusions are held right on the curved trenches, making the traction wheel move to squeeze the can wall between same and the cutting wheel such that the can wall are penetrated by the cutting wheel.